How do I deploy my api rails 5.2 in AWS ec2?

I'm following the tutorial: https://gorails.com/deploy/ubuntu/18.04#ruby

But I'm getting stuck on:
01 ArgumentError: Missing secret_key_base for 'production' environment, set this string with rails credentials:edit

How should I generate the key?
Where should I put it?
How to(key:xxxxxx or key=xxxxxxx ...)?

Please I'm in pain xP

Thank in advance

Well.! I will dive into the process and will see what I can do for the deployment of api with raw AWS EC2 server. Will get back to you with the proper answer. Till then you can try the managed version of AWS EC2 server which is powered by Cloudways. They have removed the complexities of AWS server and will let yyou enjoy the smooth experience of hosting.